Does anyone know what this aquatic plant is? it is in a pond at keele university in staffordshire uk
Looks like some sort of Iris....Blue Flag?
It's either Acorus calamus or Iris pseudacorus. Those ripples in the blade are the clincher, can't remember whether Wcorus had it ( or not). Acorus leaves would smell if crushed.
I think I'd go for Acorus calamus if pushed. Iris pseudacorus are already in bloom and tend to grow much more densely.
Acorus calamus has the waviness on the leaf, also a single prominent vein a little to one side of the middle of the blade. The spicy-sweet smell of the leaves is distinctive.